--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/langtools/src/share/classes/com/sun/tools/javac/file/ZipFileIndexCache.java	Mon Jan 24 16:38:56 2011 -0800
@@ -0,0 +1,149 @@
+/*
+ * Copyright (c) 2007, 2011, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.  Oracle designates this
+ * particular file as subject to the "Classpath" exception as provided
+ * by Oracle in the LICENSE file that accompanied this code.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+package com.sun.tools.javac.file;
+
+import com.sun.tools.javac.file.RelativePath.RelativeDirectory;
+import com.sun.tools.javac.util.Context;
+import java.io.File;
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.Iterator;
+import java.util.List;
+import java.util.Map;
+
+
+/** A cache for ZipFileIndex objects. */
+public class ZipFileIndexCache {
+
+    private final Map<File, ZipFileIndex> map =
+            new HashMap<File, ZipFileIndex>();
+
+    /** Get a shared instance of the cache. */
+    private static ZipFileIndexCache sharedInstance;
+    public synchronized static ZipFileIndexCache getSharedInstance() {
+        if (sharedInstance == null)
+            sharedInstance = new ZipFileIndexCache();
+        return sharedInstance;
+    }
+
+    /** Get a context-specific instance of a cache. */
+    public static ZipFileIndexCache instance(Context context) {
+        ZipFileIndexCache instance = context.get(ZipFileIndexCache.class);
+        if (instance == null)
+            context.put(ZipFileIndexCache.class, instance = new ZipFileIndexCache());
+        return instance;
+    }
+
+    /**
+     * Returns a list of all ZipFileIndex entries
+     *
+     * @return A list of ZipFileIndex entries, or an empty list
+     */
+    public List<ZipFileIndex> getZipFileIndexes() {
+        return getZipFileIndexes(false);
+    }
+
+    /**
+     * Returns a list of all ZipFileIndex entries
+     *
+     * @param openedOnly If true it returns a list of only opened ZipFileIndex entries, otherwise
+     *                   all ZipFileEntry(s) are included into the list.
+     * @return A list of ZipFileIndex entries, or an empty list
+     */
+    public synchronized List<ZipFileIndex> getZipFileIndexes(boolean openedOnly) {
+        List<ZipFileIndex> zipFileIndexes = new ArrayList<ZipFileIndex>();
+
+        zipFileIndexes.addAll(map.values());
+
+        if (openedOnly) {
+            for(ZipFileIndex elem : zipFileIndexes) {
+                if (!elem.isOpen()) {
+                    zipFileIndexes.remove(elem);
+                }
+            }
+        }
+
+        return zipFileIndexes;
+    }
+
+    public synchronized ZipFileIndex getZipFileIndex(File zipFile,
+            RelativeDirectory symbolFilePrefix,
+            boolean useCache, String cacheLocation,
+            boolean writeIndex) throws IOException {
+        ZipFileIndex zi = getExistingZipIndex(zipFile);
+
+        if (zi == null || (zi != null && zipFile.lastModified() != zi.zipFileLastModified)) {
+            zi = new ZipFileIndex(zipFile, symbolFilePrefix, writeIndex,
+                    useCache, cacheLocation);
+            map.put(zipFile, zi);
+        }
+        return zi;
+    }
+
+    public synchronized ZipFileIndex getExistingZipIndex(File zipFile) {
+        return map.get(zipFile);
+    }
+
+    public synchronized void clearCache() {
+        map.clear();
+    }
+
+    public synchronized void clearCache(long timeNotUsed) {
+        Iterator<File> cachedFileIterator = map.keySet().iterator();
+        while (cachedFileIterator.hasNext()) {
+            File cachedFile = cachedFileIterator.next();
+            ZipFileIndex cachedZipIndex = map.get(cachedFile);
+            if (cachedZipIndex != null) {
+                long timeToTest = cachedZipIndex.lastReferenceTimeStamp + timeNotUsed;
+                if (timeToTest < cachedZipIndex.lastReferenceTimeStamp || // Overflow...
+                        System.currentTimeMillis() > timeToTest) {
+                    map.remove(cachedFile);
+                }
+            }
+        }
+    }
+
+    public synchronized void removeFromCache(File file) {
+        map.remove(file);
+    }
+
+    /** Sets already opened list of ZipFileIndexes from an outside client
+      * of the compiler. This functionality should be used in a non-batch clients of the compiler.
+      */
+    public synchronized void setOpenedIndexes(List<ZipFileIndex>indexes) throws IllegalStateException {
+        if (map.isEmpty()) {
+            String msg =
+                    "Setting opened indexes should be called only when the ZipFileCache is empty. "
+                    + "Call JavacFileManager.flush() before calling this method.";
+            throw new IllegalStateException(msg);
+        }
+
+        for (ZipFileIndex zfi : indexes) {
+            map.put(zfi.zipFile, zfi);
+        }
+    }
+}